Cleaning and sanitization of vessels, process equipment, pipes, valves, lines, membranes and many other components that are used in food processing, biological processing and other operations are necessary and widely practiced. Typically, aqueous solutions often containing surfactants are used for the cleaning operations. For sanitization a variety of biocidal or bacteriostatic chemicals and reagents are used. The surfactants and chemicals that are used for such processes are too numerous to elaborate further. Dilution and rinsing with water before the equipment and process is ready for further operation is another important and necessary feature.
Solvents are sometimes used for such cleaning methods particularly for cleaning of difficult contaminants such as fats and denatured proteins, which can form coating layers. Alcohols are also sometimes used in combination with surfactants, polyols or other reagents.
Alcohols are known to have bacteriostatic properties and often ion exchange resins, ultrafiltration membranes and other bio-sensitive processing agents are kept in aqueous alcohol solutions for bacteriostatic preservations [Handbook of Disinfectants and Antiseptics, J. M. Ascenzi ed., Marcel Dekker, Inc, New York (1996); “Use of Benzyl Alcohol as a shipping and Storage Solution for Chromatography Media”, GE Healthcare and Life Sciences, Application Note 28-9899-01AB, General Electric Company bulletin, (2012); Barker et al., Appl Environ Microb, 67(4):1594-2000 (2001); and Oh et al., Int J Food Microbiol, 20:239-246 (1993)]. Organic acids such as formic, acetic, lactic are also known to have bacteriostatic properties [“Use of Benzyl Alcohol as a shipping and Storage Solution for Chromatography Media”, GE Healthcare and Life Sciences, Application Note 28-9899-01AB, General Electric Company bulletin, (2012); Barker et al., Appl Environ Microb, 67(4):1594-2000 (2001); and Oh et al., Int J Food Microbiol, 20:239-246 (1993)], but they have limited cleaning properties for fats, proteins and other biological contaminants.
A combination of alcohols, organic acids and other reagents can be used for cleaning and sanitization, but such combination compositions usually suffer from at least two major limitations: —1) the cleaning properties are primarily determined by the alcohol, and 2) dilution with water during and after cleaning, reduces both the solvent activity and the bacteriostatic activity.